FIGS. 8A and 8B are schematic block diagrams of prior art drive trains including a hybrid drive module. U.S. Patent Application No. 2012/0258838 discloses a hybrid drive module with an electric motor and a torque converter accepting torque from an internal combustion engine and a clutch assembly to control torque at an output of the hybrid drive module. As shown in FIG. 8A, in one embodiment, a dual mass flywheel damper is placed between the hybrid drive module and the internal combustion engine and a second vibration damper is part of the torque converter. The dual mass flywheel damper increases the axial space required for the system as well the inertia for the system.
As shown in FIG. 8B, in another embodiment, there is no vibration damper between the engine and the clutch assembly. This arrangement results in increased wear for the clutch assembly, since engine vibration is transmitted directly to the clutch assembly. In particular, spline connections and clutch plates in the clutch assembly are protected from engine vibration. Further, serviceability and assembly are complicated by the fact that the electric motor and the torque converter are assembled from the same side.
U.S. Patent Applications No. 2013/0192946 and 2013/0192947 disclose one vibration damper between a hybrid drive module and an internal combustion engine and a second vibration damper, which is part of the torque converter. FIG. 8B is applicable to both of the preceding patent application publications. The discussion for the first embodiment of U.S. Patent Application No. 2012/0258838 is applicable to the foregoing patent application publications.
FIG. 9 is a partial cross-sectional view of a prior art drive train including a hybrid drive module. In U.S. Patent Application No. 2013/0192947, a single bearing 74 is used to position rotor carrier 80, negatively impacting the positioning of the rotor carrier. Also, torque converter 49 is in a chamber, formed by transmission housing 58 filled with fluid, increasing drag associated with operation of the torque converter. Further, if chamber 58 is tipped enough, oil collects in the right side of the chamber in FIG. 9 exposes the return inlet causing the inlet to suck air instead of oil, which results in reduced performance and even damage.